Get localStorage item

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description's 'Read' adds no new behavioral information. It does not disclose what happens when the key is missing, whether the value is returned as a string or JSON, or any error behavior. Given the annotations, the bar is lower, but the description contributes nothing beyond a restatement of the read-only nature.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single concise sentence, 'Read one localStorage key.' It is front-loaded with the action and resource, with no wasted words. This is appropriately minimal for a simple tool.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a trivial single-parameter read operation, the description is minimally adequate. However, there is no output schema, and the description does not mention the return format (e.g., string value, null if missing) or any error conditions. While annotations cover the safety profile, an agent may need to know the return behavior to handle results correctly. This is a minor gap for a simple tool but prevents a higher score.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the 'key' parameter is fully documented in the schema. The description's phrase 'localStorage key' simply repeats the schema description without adding format, syntax, or expected value details. Per the baseline for high coverage, a score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Read') and a resource ('localStorage key'), clearly indicating the action. It does not explicitly differentiate from sibling tools like browser_localstorage_list or browser_sessionstorage_get, but the tool name and description are unambiguous enough for an agent to understand the purpose.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance on when to use this tool versus alternatives. The description does not mention conditions for use, exclusions, or mention any sibling tools (e.g., browser_localstorage_list for listing all keys). An agent is left to infer the appropriate context from the name alone.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.